1. Field of the Invention
The present invention relates to toner for electrophotography. More particularly, the invention relates to toner for electrophotography having an improved developing property and fixing property using rheological property.
2. Description of the Related Art
In image forming devices such as electrophotographic devices or electrostatic recording devices, an electrostatic latent image is formed through light-exposure on a photoreceptor which is uniformly charged. A toner is attached to the electrostatic latent image, and a resulting toner image is transferred to a transfer medium such as a sheet of paper. Then, an unfixed toner image is fixed on the transfer medium through several processes such as heating, pressing, solvent steaming, and so on. In most fixing processes, the transfer medium with the toner image passes through fixing rollers and pressing rollers, and by heating and pressing, the toner image is fused on the transfer medium. Toner is fixed on the transfer medium according to fixing conditions to form a stable image.
In developing processes, toner particles are transferred to a photoreceptor and selectively attached to a latent image by an electrostatic force to form a toner image on the photoreceptor. However, when the toner does not have sufficient mechanical properties, problems such as streak and blocking may occur during the developing process.
Meanwhile, if only the mechanical property is improved to facilitate the developing process, fixing property of toner may decrease. In the fixing process, the surface of a roller contacts the toner image in the melt state under pressure. Thus, toner may partially be transferred and attached to the surface of the fixing roller and transferred to a subsequent fixing sheet, thereby contaminating the subsequent fixing sheet.
Toner for electrophotography having a specific rheological property disclosed in Korean Patent No. 138,583, Korean Patent Publication Nos. 2001-083034, and 1999-063467. However, they fail to obtain both of superior developing property and fixing property. Thus, there is need for a technology that can predict the behavior of a toner to improve the developing property and the fixing property and stabilize the image quality.